Transient voltages (e.g. voltage spikes due to lightning, Electrostatic Discharge (ESD), tripped circuit breakers, short circuits, etc.) can disrupt and/or damage components in an electronic system. To protect components from the harmful effects of transient voltages, transient voltage suppression (TVS) components are commonly placed on system boards and printed wiring boards (PWB). Some examples of TVS components include varistors, transient voltage suppression diodes, and gas discharge tubes.
Unfortunately, hazardous conditions still exist on boards even when TVS components are present. The transient voltage current must pass back through the boards to ground. Therefore, even though the TVS components are designed to protect other electronic components on a board, the transient voltage current is still on the board. In the event of failed or defective TVS components, the transient voltage is on the board with the potential to disrupt or damage the other electronic components. It can be costly to replace the components damaged by transient voltages and to repair or replace defective TVS components.
Like reference numbers and designations in the various drawings indicate like elements.